The purpose of this project is to elaborate and define the effects of U.V. radiation (340-390 nm) on the ocular lens, particularly on specific protein fractions. Such radiation appears to result in the development of one or more fluorogens associated with certain lens proteins and these fluorogens may play a role in the polymerization and insolubilization of the soluble lens proteins, to form the insoluble protein fraction of the lens. Aside from the role of the fluorogen in the aging process, it may also be a significant pathogenetic factor in nuclear cataract formation. An in vitro and in vivo approach will be utilized. Whole lenses from various species (including the human) will be examined by fluorescence spectroscopy, and lens incubates will be subjected to U.V. radiation to determine the metabolic effects of such exposure as well as to analyze and define the fluorogens formed. Specific lens protein fractions will be extracted and the fluorogens isolated from these fractions, as well as the peptides in which the fluorogen is present. The fluorogens will be subjected to various forms of spectroscopic analyses in an effort to determine the nature of the fluorogen(s) and the changes that may develop in their peptides and the proteins from which they derive. The tools utilized will include fluorescence, I.R., U.V. and E.S.R. spectroscopy and mass spectrometry.